GMB members, who were supplying T-shirts to those attending the protest, say they heard the comment being made and reported it to council leader Jim Logue.

Regional organiser Hazel Nolan said: “I’m not sure whether the councillor was trying to be tongue-in-cheek but I was absolutely disgusted – it’s not a great joke and it’s certainly not a issue to joke about for these women.”

Plains resident Sandra Barron said of Councillor Docherty: “He walked past us at front door of the Civic Centre and as he entered, called out, ‘give me one of your T-shirts and I’ll use it as a duster.’ A crowd of us heard it.”

Councillor Docherty said: “I don’t recall anything about it; I wouldn’t like to make any comment on it.”

Councillor Logue confirmed that a complaint was made by protesters, which he has referred on to party business manager Councillor Heather McVey.

He said: “I’ve asked her to look into the complaint to see if there’s any basis to it, which she’ll do.

“I would take a dim view of anything negative. This is a very serious issue for everyone and we’re trying to get a resolution.”

The council leader will be meeting GMB representatives this afternoon in an attempt to make progress with the long-running dispute, in his first such meeting since taking over the top post five weeks ago.

Councillor Logue said: “We’ve already paid out over £100 million in equal pay settlements so it’s not us being niggardly – everything has to be checked for accuracy, which is critical. It’s a complex issue.

“One of the reasons why I want to meet directly with union representatives is to talk to them and get an overview of where they’re coming from and to look at what, if anything, we can do to accelerate payments that people are entitled to.”

Home support worker Sandra was among told the Advertiser she was offered just over £3000 as a settlement – while a council colleague who started at the same time received £42,000.

She said: “I’ve been in this job for the past 15 years and have always given 100 per cent looking after the frail, the elderly and doing palliative care, and I’m not getting paid the same as my colleagues.

“It’s demoralising; I feel ashamed that I have to go to meetings like this to claim money that is actually mine from my own employer.

“I’ve been going to meetings for the past nine years and even had to take a day’s holiday to go to the protest; it’s shameful.”

SNP politicians including Neil Gray MP joined the protesters at the council headquarters demonstration.

He said: “The women protesting here today have worked hard and given loyal service to the council, and these claims should have been sorted out a long time ago; it’s a scandal.

“The council has spent an estimated £80m fighting these claims through the courts. It’s high time that Labour and Jim Logue sort this situation out by paying these women what they’re owed.”

Airdrie and Shotts SNP constituency candidate Alex Neil also pulled no punches, stating the money used by the council in legal fees could have saved vital public services.

He said: “It’s a disgrace a Labour-run council can have their own workers demonstrating outside their front door. The £80m to £100m they have spent on legal fees could have saved many of the public services that have been cut over the past few years.

“I wouldn’t trust this council to run a stall never mind a council. They are acting like Tories.”